Problem: Simplify the following expression: $a = \dfrac{n + 1}{2n + 8} - \dfrac{6n + 11}{2n + 8}$
Since the expressions have the same denominator we simply subtract the numerators: $a = \dfrac{n + 1 - (6n + 11)}{2n + 8}$ Distribute the negative sign: $a = \dfrac{n + 1 - 6n - 11}{2n + 8}$ Combine like terms: $a = \dfrac{-5n - 10}{2n + 8}$